Transpormer-coil por ignition



J. CAVANAGH. TRANSFORMER COIL FOR IGNITION, dac.

APPLICATION FILED IIIAY28119I8.

Patented Aug. 5,

7 V K i' mvmmn m m I 5 mwmmmwm I I I JOHN F. CAVANAGH, 0F MEBIDEN,

PHONE 85 ELECTRIC 00., INCL, OF MEBIDEN,

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CONNECTICUT, ABBIGNOR TO CONNECTICUT TELE- GONNEC'IICUT, A CORPORATION OF ramsroamsacon. ron IGNITION, an.

I Specification of Letters Patent.

Patented Aug. 5, 1919.

Application filed Kay 28, 1918. Serial 110. 287,160.

To all whom it may concern:

Be it known that I, Joan F. Oavarmsn, a citizen of the United States of America, residing at Meriden, Connecticut, have invented a new and useful Transformer-Co l for Ignition, &.c., of which the following is a specification.

My present invention relates to spark coils for electric ignition systems and the general objects of the invention are to improve such coils both from an electrical and a structural standpoint.

Special objects of the invention are to ain increased electrical efiiciency and therey enable a reduction in size of the coil and quantity of materials used, to intensify the reduce sparking at ignition spark and to the breaker points of the primary circuit and to provide a coil which will be relatively small, compact and well protected.

These obJects I have accomplished by constructing the coil with the secondary about the core and the primary about the secondary and by pllaclng the condenser about the primary, t e whole being in in a magnetic shell to the ends of which insulating heads or end caps are applied forming supports for the terminals. Preferably the high tension terminal is mounted on one of the insulating end caps and all the other terminals are mounted on theother insulating end cap.

Other features of the invention will appear as the specification proceeds.

In the accompanying drawing I have illustrated the invention embodied in a practical commercial form, this with the understanding1 however, that such disclosure is merely ustrati've of the invention and that changes and modifications may be made without departure from the true spirit and see c of the invention.

11 said drawing Figure 1, is a longitudinal sectional view of the coil. p

Fig. 2, is a broken side elevation thereof.

Fig. 3,, is a more or less diagrammatic representation of the invention as appli to a typical battery distributer system. I

Consideriu the drawing now in detail; 5 designates e magnetic core which may be constructed of iron wire or other material, as customary. 6 desi tes winding applied in this case directly to the appliedto the sec ndary the secondary, suitable insulatingelayers 8 and 9 being usually in- I tween the core and the secondary winding and between the two windings res and surrounding v 10 designates the condenser which in accordance with this invention is placed outside and surrounding-the primary winding, said condenser bei usually made up of alternating layers 0 foil and a suitable dielectric and the whole coiled about or sleeved over the primary.

11 designates the outer magnetic shell or casing which incloses the condenser and windlngs and serves both structurally as a housing and magnetically as a part of the etic circuit.

12 and 13 designate the and heads or caps made of insulating material and applied to the ends of the magnetic shell so as to form a complete inclosurc for the various parts. These end caps are secured in place in the present disclosure by a securing screw H extending through the core and havin nuts 15 engaged with the threaded extended ends thereof for forcing the end caps into close fitting engagement with the shell.

In accordance with my invention all the low tension terminals are mounted on the one end cap 12 and the high tension terminal is mounted on the opposite end cap and therefore comparatively far-removed from the low tension terminals. In the illustration 16 and 17 designate the terminals for the primary winding and 18 a terminal in the primary circuit, all mounted on the end cap 12. 19 designates the secondary or high tension terminal mounted within a tubular housing or extension 20 on the opposite end cap 13 said housing being constructed to receive the end of the high tension cable.

A typical circuit arran ement' for the coil is illustrated in Fig. 3 w erein the battery 21 is shown connected y a lead 22 with the primary terminal 16. The other primary terminal 17 is connected by a lead 23 wit the breaker arm of the circuit interrupter 24, the other side of the circuit interrupter being connected by a lead 25 with the terminal 18. From this terminal 18 a connec tion is made as indicated at 26, with the magnetic shell, which serves as a ground, said shell being suitably grounded on the frame of the car or o her structure as by means of its supporting bracket 27. Thli forms the primary circuit, it being noted that the opposite side of the batter is grounded as indicated at 28. The secon ary coil is grounded at one end as by means of the connections 29-26 and at its opposite end is connected as by means of a high tension cable 30 with the arm of the distributor 31, which is connected in the usual way with the sparking appliances. The condenser is connected across the breaker points as by means of connections 3226 and 33.

In this invention the secondary is placed close to the core and hence in the strongest part of the magnetic field, while the primary is disposed in a comparatively weak portion of the magnetic field. This tends to produce a minimum counter E. M. F. in the primary resulting in a minimum amount of sparking at the breaker points while the location of the seoondar in the strongest part of the magnetic fie d causes it to be energized to a maximum degree. In other words, the highest electrical efiiciency is obtained from both the secondary and the primary, and this results in the production of a very hot and efficient ignition s ark.

Also, in my construction, the condenser is far removed from the influence of the secondary winding and is at a point where the leads from the secondary, primary and condenser are common in that there is practicaily no difference in potential. Another turn magnetic path.

important point of advanta e is that by the location of the condenser a j acent the shell, said condenser is disposed in the coolest part of the construction, resultin in the condenser being kept relatively coo and without the variation in capacity which arises from heatin of a condenser.

Structure y, the invention ossesses many advantages particularly in the ease of assembla the small size and compactness of the coi and the fact that it is weather-proof with all parts thoroughly protected;

I claim:

1. In a spark coil, the combination of a step-up secondary winding, a rimary winding surrounding said secon ary winding, and a condenser surrounding said primary winding, and thereby relatively far removed from the influence of the secondary.

2. In a combination like that set forth in claim 1, a magnetic shell disposed outside said primary winding and providing a re- 3. In aspark coil, primar and secondary windings, a magnetic sh 'inclosing the same, end caps of insulating material applied to said magnetic shell, low tension termlnals on one of said end caps, and a high tension terminal on the opposite end cap and removed from the low tension terminals.

JOHN F. CAVANAGH. 

